Experimental spectral data agree well with the theoretical findings. The UV–Vis spectra of (4a-d) show π→π∗ and n→π* electronic transitions. The β0 values (7.40–9.05 × 10−30 esu) indicate the suitability of (4a-d) compounds NLO response. The binding energy of (4a-d) compounds are found in the range of 10.10–11.19 kcal/mol.